Merge branch 'mv88e6xxx-fixes'

Marek Behún says:

====================
mv88e6xxx fixes (mainly 88E6393X family)

sending v2 of these fixes.

Original cover letter:

So I managed to discovered how to fix inband AN for 2500base-x mode on
88E6393x (Amethyst) family.

This series fixes application of erratum 4.8, adds fix for erratum 5.2,
adds support for completely disablign SerDes receiver / transmitter,
fixes inband AN for 2500base-x mode by using 1000base-x mode and simply
changing frequeny to 3.125 GHz, all this for 88E6393X.

The last commit fixes linking when link partner has AN disabled and the
device invokes the AN bypass feature. Currently we fail to link in this
case.

Changes since v1:
- fixed wrong operator in patch 3 (thanks Russell)
- added more comments about why BMCR_ANENABLE is used in patch 6 (thanks
  Russell)
- updated some return statements from
     if (something)
       return func();
     return 0;
  to
     if (something)
       err = func();
     return err;
  (err is set to 0 before the condition)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>